//  ValueComparator.java
//
//  Author:
//       Antonio J. Nebro <antonio@lcc.uma.es>
//       Juan J. Durillo <durillo@lcc.uma.es>
//
//  Copyright (c) 2011 Antonio J. Nebro, Juan J. Durillo
//
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
// 
//  You should have received a copy of the GNU Lesser General Public License
//  along with this program.  If not, see <http://www.gnu.org/licenses/>.

package etmo.qualityIndicator.util;

import java.util.Comparator;

/**
 * This class implemnents the <code>Comparator</code> interface. It is used to
 * compare points given as <code>double</code>. The points are compared taken
 * account the value of a index
 */
public class ValueComparator implements Comparator {

	/**
	 * Stores the value of the index to compare
	 */
	private int index_;

	/**
	 * Constructor. Creates a new instance of ValueComparator
	 */
	public ValueComparator(int index) {
		index_ = index;
	}

	/**
	 * Compares the objects o1 and o2.
	 * 
	 * @param o1
	 *            An object that reference a double[]
	 * @param o2
	 *            An object that reference a double[]
	 * @return -1 if o1 < o1, 1 if o1 > o2 or 0 in other case.
	 */
	public int compare(Object o1, Object o2) {
		// Cast to double [] o1 and o2.
		double[] pointOne = (double[]) o1;
		double[] pointTwo = (double[]) o2;

		if (pointOne[index_] < pointTwo[index_]) {
			return -1;
		} else if (pointOne[index_] > pointTwo[index_]) {
			return 1;
		} else {
			return 0;
		}
	} // compare
} // ValueComparator
